Hydraulic pressure intensifier

ABSTRACT

The invention relates to a hydroelectric pressure intensifier in which the plunger piston ( 8 ) and/or the driving spindle ( 9 ) of said plunger piston and/or the piston rod ( 3 ) of the working piston ( 2 ) are driven by electrical means, especially electromotors such as linear motors ( 11 ).

STATE OF THE ART

[0001] The invention originates from a hydraulic pressure intensifier according to the kind of the main claim. With a well-known hydraulic pressure intensifier according to the generic kind (DE-OS 42 23 411) the piston spindle of the plunger is actuated via a pneumatic drive piston for the generation of high pressure. Thereby a direct dependence on a pneumatic supply of this pressure intensifier consists, which in some cases is not given, respectively is always connected with certain efforts and makes the application of the device dependent on such an air supply.

THE INVENTION AND ITS ADVANTAGES

[0002] The hydraulic pressure intensifier according to the invention with the characteristic features of the main claim has in contrast to this the advantage to be independent of a compressed air supply and to be supplied by an always present energy, i.e. the electric current. In contrast to this are such units, as above mentioned units of the state of the art, in which hydraulics or pneumatics is controlled via valves, which in turn supply the pressure intensifier with media, i.e. pressure and hydraulic oil of entered energy (DE-OS 26 25 884). The disadvantage of the relying dependence on such power suppliers consists also here in contrast to the invention, in which the hydraulics only within the pressure intensifier for the conversion of the piston motion driven with relatively low force to a hydraulic high pressure, with suitable driving power of the working piston. Already low stroke forces, created by electricity, are sufficient, in order to create hydraulic high pressure. Thereby it is quite conceivable that also the driving power generated by the electrical energy in the electrical working means is controlled, for example by generating a lower force for rapid traverse and when immersing the plunger piston into the working area an electrical commutation takes place due to the higher pressure given there thereby, respectively due to the mechanical procedure. This is also an additional advantage of the inventive solution.

[0003] According to a favorable embodiment of the invention an electric motor serves as driving means, which can be designed in various ways; it is decisive that at least indirectly a stroke takes place, thus a linear motion of the driving spindle, respectively of the plunger piston, and then for the working stroke, the piston rod.

[0004] According to a relevant favorable embodiment of the invention a ball spindle motor or such serves as electrical driving means. Also here are besides ball spindles and trapezoid spindles various designs existent, with which the rotary motion of the motor is converted into a linear motion of the driving spindle by the arrangement of the spindle wall and the drive means.

[0005] According to an alternative embodiment of the invention the electric motor is designed as linear motor, with which the plunger is at least indirectly connected with the plunger piston and/or the piston rod of the working piston, so that especially the rapid traverse movement can take place via the linear forces and whereby the driving spindle can serve as rotor of the linear motor. When using such a linear motor at the piston rod, then given retaining forces, due to the high pressure transmission, can be easily overcome after immersing the plunger piston into the working area at the linear motor, whereby a quick adjustment is possible particularly during rapid traverse movement and return stroke.

[0006] According to an additional favorable embodiment of the invention the rapid traverse stroke lying before the working stroke and/or the return stroke lying behind the working stroke are caused at least partially hydraulically.

[0007] According to a relevant favorable embodiment of the invention an annular area for hydraulic control is present within the housing and around the piston rod, as well as limited by the working piston. The hydraulic servo function thereby made possible allows the application of well-known means, like a servo drive and such.

[0008] According to a relevant favorable embodiment of the invention a hydraulic connection consists between annular area and storage volume.

[0009] According to a relevant additional embodiment of the invention around the driving spindle an annular piston is axially movable arranged, which is sealed towards the driving spindle and to the housing; said annular piston limits a compensation area, which is filled with hydraulic fluid, towards the storage piston and is loaded by a spring determining the hydraulic low pressure on the side opposite to the storage piston, and

[0010] which is connected with the hydraulic connection. This compensation area 14 causes due to the spring a constant pressure in the storage volume and in the annular area, at least during the return stroke.

[0011] According to a relevant favorable embodiment of the invention a control valve is arranged in each case in the hydraulic connection between the storage volume and the annular area, respectively the compensation area, which as one-way valve blocks in the flow direction out of the annular area or the storage volume, however throttles in the flow direction to these areas.

[0012] According to an additional favorable embodiment of the invention the driving spindle respectively the piston rod can be driven by a linear motor, as already suggested above.

[0013] Further benefits and favorable embodiments of the invention can be taken from the following description, the drawing and the claims.

DRAWING

[0014] Two design examples of the invention are represented in the drawing and following described in more detail. Shown are:

[0015]FIG. 1 a hydraulic electrical pressure intensifier in the profile and

[0016]FIG. 2 highly simplified a suitable alternative example.

DESCRIPTION OF THE DESIGN EXAMPLES

[0017] The same components or components of same function present in the two design examples are termed in the following with the same reference number.

[0018] A working piston 2 in a housing 1 of a hydraulic pressure intensifier drives a piston rod 3 and a hydraulic working area 4 is intended. In addition a storage volume 5 is intended, which is connected with the working area 4 by a control bore 6 and is limited by a storage piston 7. A plunger piston 8 is intended coaxially with the storage piston 7, which is connected with a driving spindle 9, which immerses into the control bore 6 after traveling a certain stroke, blocks said control bore and creates during the continuation of the stroke in the working area 4 a high pressure given according to the diameter ratio of plunger piston 8 and working piston 2. During a first stroke, i.e. rapid traverse, the piston rod 3 is driven near to the work piece, whereby then with the plunger piston 8 a force stroke is created for the machining of the work piece, for example a punching of the same.

[0019] In the design example represented in FIG. 1 a driving spindle 9 is attached with the storage piston 7 in axial line with the plunger piston 8, which penetrates a linear motor 11, which is arranged outside of the housing 1 and attached to said housing. As soon as the piston rod 3 finishes the rapid stroke and the plunger piston 8 is immersed into the control bore 6, the stroke of this plunger piston 8 is continued by the linear motor, for the generation of a high pressure in the working area 4 and a corresponding feed of the piston rod 3. Coaxially to the driving spindle 9 an annular piston 12 is arranged axially movable on said driving spindle; said annular piston is loaded by a spring 13 and is limited on the side opposite to the spring 13 by a compensation area 14, which is in turn limited by the storage piston 7.

[0020] This compensation area 14 is connected by a line 15 both with the storage volume 5 and with an annular area 16, which is formed between working piston 2, housing 1 and piston rod 3. Control valves 17 are arranged in the line sections once to the annular area 16 and to the storage volume 5, which ensure in each case a free flow to the storage volume 5 respectively to the annular area 16,

[0021] which however in reverse direction throttle the through flow, whereby this throttling can be adjusted. While the flow to these areas serves the return stroke course of the device, the throttling effect occurs during the rapid traverse movement respectively the working stroke of the pressure intensifier.

[0022] In the only very much simplified design example represented in FIG. 2 also the piston rod 3 can be driven by an only generally represented spindle drive 18, which is designed in particular as linear motor. In addition a servo drive 19, an additional reservoir 21 for hydraulic fluid and a asynchronous motor 22 can be taken from FIG. 2, which actuates a spindle drive 23 of the spindle 24, which is again connected coaxially with the plunger piston 8.

[0023] All features represented in the description, the following claims and the drawing can be relevant for the invention both individually and in arbitrary combination with one another.

[0024] Reference Number List

[0025]1 Housing

[0026]2 Working piston

[0027]3 Piston rod

[0028]4 Working area

[0029]5 Storage volume

[0030]6 Control bore

[0031]7 Storage piston

[0032]8 Plunger piston

[0033]9 Driving spindle

[0034]10

[0035]11 Linear motor

[0036]12 Annular piston

[0037]13 Spring

[0038]14 Compensation area

[0039]15 Line

[0040]16 Annular area

[0041]17 Control valve

[0042]18 Spindle drive

[0043]19 Servo drive

[0044]20

[0045]21 Reservoir

[0046]22 Motor

[0047]23 Spindle drive

[0048]24 Spindle

[0049] Hydraulic Pressure Intensifier 

1. Hydraulic pressure intensifier with a working area (4) arranged in an aggregate housing (1) for changing pressures, i.e. a low storage pressure for a rapid traverse advance and a return stroke as well as a high working pressure for a working stroke, with a working piston (2), limiting the working area (4) at the front side and actuated by the working pressure in the working housing (1) for the working stroke; said working piston is guided by a piston rod (3) to the outside of the housing (1), with a storage volume (5), hydraulically connected with the working area (4), arranged in a cylindrical space of the housing (1); hydraulic oil under storage pressure flows out of said storage volume during rapid traverse into the working area (4) and flows back again with the return stroke, with a plunger piston (8) that can be actuated as high pressure generator and is immersing into the working area (4) after rapid traverse, exhibiting a driving spindle (9), with a drive unit of the plunger piston (8) on the opposite side of the working area (4) for rapid traverse and also for the working stroke for the generation of the high working pressure characterized by the fact, that the plunger piston (8), respectively the driving spindle (9) is driven at least for the working stroke by electrical working means (11, 18, 22, 23).
 2. Pressure intensifier according to claim 1, characterized by the fact that an electric motor (11, 18, 22) serves as driving means.
 3. Pressure intensifier according to claim 2, characterized by the fact that a ball spindle motor or such serves as electrical driving means.
 4. Pressure intensifier according to claim 2, characterized by the fact that the electric motor is designed as linear motor (11), with which the plunger is at least indirectly connected with the plunger piston (8) and/or the piston rod (3) of the working piston (2)
 5. Pressure intensifier according to one of the preceding claims, characterized by the fact that the rapid traverse stroke lying before the working stroke and/or the return stroke lying behind the working stroke are caused at least partially hydraulically.
 6. Pressure intensifier according to one of the preceding claims, characterized by the fact that an annular area (16) for hydraulic control, in particular for the return stroke is present within the housing (1) and around the piston rod (3), as well as limited by the working piston (2).
 7. Pressure intensifier according to claim 6, characterized by the fact that a hydraulic connection (15) consists between annular area (16) and storage volume (5).
 8. Pressure intensifier according to claim 7, characterized by the fact that around the driving spindle (9) an annular piston (12) is axially movable arranged, which is sealed towards the driving spindle and to the housing (1); said annular piston limits a compensation area (14), which is filled with hydraulic fluid, towards the storage piston (7) and is loaded by a spring (13) determining the hydraulic low pressure on the side opposite to the storage piston (7), and is connected with the hydraulic connection (15).
 9. Pressure intensifier according to claim 8 or 9, characterized by the fact that a control valve (17) is arranged in each case in the hydraulic connection between the storage volume (5) and the annular area (16), respectively the compensation area (14), which as one-way valve blocks in the flow direction out of the annular area (16) or the storage volume (5), however throttles in the flow direction to these areas.
 10. Pressure intensifier according to one of the claims 4 to 10, characterized by the fact that the driving spindle (9) respectively the piston rod (3) can be driven by a linear motor. 